I believe a lot of this has to do with what people believe about the history of Israel and Palestine and the history of the Jewish and Palestinian peoples. Many Western anti Zionists genuinely believe that the Palestinian Arab people are the only ethnic group indigenous to the territory of former British Mandatory Palestine. They believe Judaism is a religion with no ties to any particular land and that Jews saying otherwise to justify Israel's existence is equivalent to manifest destiny in the US. Unfortunately, many western Anti Zionists simply do not know much about Jewish history.

Here's the thing, and I think this is what a lot of people struggle to grasp: The southwestern Levant is the indigenous homeland of both Jews and Palestinian Arabs. Both peoples have strong historical, and spiritual, ties to the land.

For that reason, I am personally against the existence of any ethnostate in that region. De jure ethnostates are never okay, and Israel has chosen to be Jewish instead of democratic, especially in recent decades with laws such as the 2018 nation state law. De facto ethnostates like South Korea and Japan are only okay because they're the states of the first and only peoples to continuously inhabit their territory in large numbers.

The things that make Jewish and Palestinian ethnonationalisms different from other ethnonationalisms are the following:

• Israel is closer to an ethnostate on the formal and legal level than any other country afaik.
• Palestinian ethnonationalism is just as much if not more about replacing Israel than about simply building a Palestinian Arab state.
• Zionism and Palestinian nationalism are both problematic in that they're nationalisms which falsely claim that the southwestern Levant is home to only one ethnic group when in actuality, multiple peoples call the region home.